Field of the Invention
The invention is in the field of medical technology and concerns a method and an implant for stabilizing two bone portions separated by a cut or fracture in a human or animal patient, in particular for stabilizing two bone portions being separated by osteotomy.
Description of Related Art
Osteotomy is a surgical procedure in which a bone is cut with the aim of being shortened, lengthened or re-aligned. Osteotomy is performed on human and animal patients mainly for realigning the load bearing surfaces in joints and for realigning bone portions in particular in the facio-maxillar region but also for re-aligning bone portions healed together with an undesired alignment relative to each other after a fracture. The bone portions separated by the osteotomy procedure mostly need to be re-aligned in a desired position relative to each other and to be stabilized in this position for being able to heal together again. According to the state of the art, osteotomy sites are usually stabilized with the aid of plates (e.g. metal plates) which are positioned on the bone surface across the osteotomy cut and are fastened in this position with the aid of bone screws or nails. According to the state of the art, simple bone fractures are stabilized in the same manner.
The named stabilization of cut or fractured bones with the aid of plates and bone screws is well established but it is of an only limited efficiency, mainly because the plates are preformed and therefore are to be available in a large number of different types for a large number of different applications and different patients. Furthermore, metallic plates and screws need to be removed in most cases, which make further surgery necessary when the cut or fractured bone is healed.
Well known applications of osteotomy concern e.g. human hip or knee joints and serve for re-aligning the articular surfaces of the joint in order to correct dysplasias and deformities by improvement of the alignment and/or the interaction of the articulating bones, or for relieving arthritic pain by re-aligning partly damaged articular surfaces to shift the bearing of the load from damaged to still healthy regions of the articular surfaces. Further well known osteotomy applications concern mandible or maxilla re-alignment e.g. for correcting discrepancies in tooth positions, or concern the chin bone for correcting or improving a person's profile. In veterinary medicine osteotomy is used e.g. for treating canine stifle joints suffering from cranial cruciate ligament rupture or damage, by tibial plateau leveling or tibial tuberosity advancement, both these treatments serving for reducing tibiofemoral shear forces during weight bearing which shear forces become large enough for damaging the joint, when the cranial cruciate ligament is damaged.